The art of glass container manufacture is currently dominated by the so-called individual section or IS machine. Such machines include a plurality of separate or individual manufacturing sections, each of which has a multiplicity of operating mechanisms for converting one or more charges or gobs of molten glass into hollow glass containers and transferring the containers through successive stages of the machine section. In general, an IS machine system includes a glass source with a needle mechanism for controlling a stream of molten glass, a sheer mechanism for cutting the molten glass stream into individual gobs, and a gob distributor for distributing the individual gobs among the individual machine sections. Each machine section includes one or more parison molds in which a glass gob is initially formed in a blowing or pressing operation, one or more invert arms for transferring the parison blanks to blow molds in which the containers are blown to final form, tongs for removing the formed containers onto a deadplate, and a sweepout mechanism for transferring molded containers from the deadplate to a cross conveyor. The conveyor receives containers from all sections of an IS machine, and conveys the containers to a loader for transfer to an annealing lehr. Operating mechanisms in each section also provide for closure of mold halves, movement of baffles and blowing nozzles, control of cooling wind, etc. U.S. Pat. No. 4,362,544 includes a background discussion of the art of both "blow and blow" and "press and blow" glassware forming processes, and also discusses an electropneumatic individual section machine adapted for use in either process.
The various operating mechanisms of the IS machine system were initially operated and synchronized with each other by means of a machine shaft, a multiplicity of individual cams rotatably carried by the shaft, and pneumatic valves responsive to the cams for selectively feeding air under pressure to the various operating mechanisms. The current trend in the art is toward replacement of the shaft, mechanical cams and pneumatic actuators with electric actuators responsive to drivers operated by so-called "electronic cams." These electronic cams take the form of motion profile information for the various operating mechanisms stored in electronic memory and selectively retrieved by electronic control circuitry for operating the electric actuators. Thus, such motions as forming and severing of the glass gobs, moving of the parisons and containers, opening and closing of the blow molds, in and out motions of the funnels, baffles and blow heads, and motions of the sweep-out and lehr-loading devices are accomplished electronically from motion profile information digitally stored in electronic memory, with motions at the various machine sections being synchronized with each other by common clock and reset signals. See U.S. Pat. No. 4,762,544.
In IS machine glassware forming systems that employ mechanical actuating cams on a machine shaft, adjustment of timing and motion profiles of the various operating mechanisms required adjustment or replacement of individual cams. In systems that employ electronic cams, it is often still necessary to stop the machine or machine section, change the motion profile electronically, and then restart the machine. For example, control techniques of the type disclosed in U.S. Pat. No. 4,548,637 typically require generation and storage of new profile data in an electronic read-only memory, often at a location remote from the glassware manufacturing plant, and shut-down of the manufacturing system to permit installation of the memory in the control electronics.
A system was employed by applicants' assignee beginning in about the mid 1980's for electronically designing the actuating cams of a cam-operated lehr loader mechanism of the type shown in U.S. Pat. No. 4,290,517. In this computer-based system, the operator was prompted to enter a number of profile and machine parameters, following entry of which motion profiles for the loader bar forward and sideshift axes were automatically generated from equations prestored in computer memory. The system was capable of displaying calculated profiles (position, velocity and/or acceleration) for operator observation and verification, and/or printing such profiles on a stripchart-type recorder. The system also provided for a graphic display on an operator screen simulating motion of the lehr loader bar relative to containers on the cross conveyor, from which the operator could verify motions of the loader bar and identify possible interference between the loader bar and glassware on the cross conveyor. When the desired forward and sideshift motions had been observed and verified, the system prepared a numeric controlled tape from which mechanical cams could be generated employing conventional CNC processes for obtaining the desired forward and sideshift motions at the lehr loader.
Although the system so described addressed and overcame many problems associated with manual design of mechanical cams and may be readily implemented in corresponding design of electronic cams, further improvements remain desirable. For example, the prior art system accommodated some variations along the forward and sideshift axes, but did not accommodate electronic design along the lift axis of the loader bar. Furthermore, mechanical linkage between the forward and sideshift axes in the lehr loader mechanism was such as to reduce flexibility of profile design due to the lack of independence of motion along these two axes. That is, the forward and sideshift axes were required to have a specified relationship, which could not accommodate independent motion between these axes. The velocity of the loader bar relative to the glassware at the moment of contact between the loader bar and the glassware was not controllable. There was an automatic 50/50 split between advance and return strokes of the loader bar, further reducing flexibility of motion design. Furthermore, the return motions were always the reverse of the advance motions, further reducing design flexibility.
It is a general object of the present invention to provide a system and method for selectively designing and/or modifying the motion profiles of the loader bar in the lehr loader mechanism of a glassware forming system having greater design flexibility than systems heretofore proposed, as discussed above. Another and related object of the invention is to provide a system and method of the described character in which the motion profiles may be controlled independently of each other. A further object of the present invention is to provide a system and method for lehr loader profile control that may be readily implemented in a manufacturing environment with a minimum of operator training. A more specific object of the present invention is to provide a method and system for generating motion control profiles for a lehr loader mechanism in which profile data can be readily changed, in which profile modifications are made off-line while the system is operating, which are user friendly, and which can be readily employed for creating and storing a library of lehr loader motion control profiles that may be later selected for use by an operator. Another and yet more specific object of the present invention is to provide a method and system for generating motion control profiles for the lehr loader mechanism of an IS machine system by means of which plant personnel are allowed to select and/or modify the motion profiles to obtain optimum performance at the lehr loader for a given set of container handling conditions, that allow such profile selection and/or modification on an immediate basis, in which a plurality of standard profiles may be selectively generated and stored, and that operate by means of a Windows-based operating system.